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September 2012

Drift Trajectory Analysis of a ... Whale Carcass?!

Trajectory followed by the Prestige ship in November
2002, most of it inside the present SeaSonde
coverage area (Images courtesy of Puertos del
Estado and INTECMAR).

In 2002, the Prestige oil spill disaster off the northwestern coast of
Spain acted as a wake up call highlighting the importance of preparing
for such a crisis. It led to Spanish institutions prioritizing the
improvement of activities such as maritime protection, operational
oceanography and oil spill preparedness and response. As part of this, ten
years after the Prestige, a Galician SeaSonde HF radar network provides
real time surface currents, wave data and currents forecast information
covering 280 km or 75% of Galicia coast and with a range of up to 200 km
offshore. Its operation and exploitation is the responsibility of Puertos del
Estado www.puertos.es, INTECMAR www.intecmar.org and
www.meteogalicia.es.

The present use of the data is wide; an exemplary case on how the data are
being used is a drifting object trajectory forecast analysis done in
December 2011 for the Directorate of the Spanish Merchant Marine. A
drifting whale was identified the 12th of December by the Spanish Coast
Guard at 22 00 h UTC in position 42°22’N 09°23’W. Intermediate
positions of the whale were monitored at that time; landing happened the
14th of December at 21 39 h UTC, as notified by the Vigo Rescue
Coordination Center of the Spanish Coast Guard.

Trajectory of a whale
along Galician waters
(Data courtesy of the
Spanish Merchant
Marine Administration)
and trajectory forecast
model done by IH using
the “Lagrangian Model
TESEO”.

Value analysis of the Galician operative OMA STP currents
prediction system in a trajectory forecast with regards to a
situation with only wind data.

An analysis to assess the qualitative improvement by using
SeaSonde currents and OMA-STP forecast system together
with a trajectory model was performed against results
provided by a standard trajectory forecast based only on
wind data. The analysis of the whale trajectory as presented
was done by IH Cantabria www.ihcantabria.com in
collaboration with QUALITAS www.qualitasremos.com based on the OMA-STP currents which are delivered in an
operational mode as part of the PORTUS by QUALITAS®
Marine Information System along the Galician coast and the trajectory forecast models that are currently being used by the
Spanish Coast Guard (ASA OILMAP™ and TESEO Lagrangian Model). The results contained in the adjacent table make clear
that the use of OMA-STP currents can greatly improve trajectory forecast models (around 80% for this experiment) in areas
which are close to the coast and where HF Radar systems are able to provide high quality surface currents information.